|Protein Science (2009) 18:2410-9|
|Midwest Center for Structural Genomics|
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The structure of AF2331, a 11-kDa orphan protein of unknown function from Archaeoglobus fulgidus, was solved by Se-Met MAD to 2.4 A resolution. ...
The structure consists of an alpha + beta fold formed by an unusual homodimer, where the two core beta-sheets are interdigitated, containing strands alternating from both subunits. The decrease in solvent-accessible surface area upon dimerization is unusually large (3960 A(2)) for a protein of its size. The percentage of the total surface area buried in the interface (41.1%) is one of the largest observed in a nonredundant set of homodimers in the PDB and is above the mean for nearly all other types of homo-oligomers. AF2331 has no sequence homologs, and no structure similar to AF2331 could be found in the PDB using the CE, TM-align, DALI, or SSM packages. The protein has been identified in Pfam 23.0 as the archetype of a new superfamily and is topologically dissimilar to all other proteins with the "3-Layer (BBA) Sandwich" fold in CATH. Therefore, we propose that AF2331 forms a novel alpha + beta fold. AF2331 contains multiple negatively charged surface clusters and is located on the same operon as the basic protein AF2330. We hypothesize that AF2331 and AF2330 may form a charge-stabilized complex in vivo, though the role of the negatively charged surface clusters is not clear.
|chemistry genetics metabolism |
|Computational Biology Crystallography, X-Ray Models, Molecular Archaeal Proteins Protein Structure, Tertiary Protein Conformation Protein Folding Protein Multimerization Archaeoglobus fulgidus |
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